Polar vortex visits to U.S. linked to climate change

Climate Change

WASHINGTON (AP) — Remember the polar vortex, the huge mass of Arctic air that can plunge much of the U.S. into the deep freeze? You might have to get used to it.

A new study says that as the world gets warmer, parts of North America, Europe and Asia could see more frequent and stronger visits of that cold air. Researchers say that's because of shrinking ice in the seas off Russia.

Normally, the polar vortex is penned in the Arctic. But at times it escapes and wanders south, bringing with it a bit of Arctic super chill.

That can happen for several reasons, and the new study suggests that one of them occurs when ice in northern seas shrinks, leaving more water uncovered.

Normally, sea ice keeps heat energy from escaping the ocean and entering the atmosphere. When there's less ice, more energy gets into the atmosphere and weakens the jet stream, the high-altitude river of air that usually keeps Arctic air from wandering south, said study co-author Jin-Ho Yoon of the Pacific Northwest National Laboratory in Richland, Wash. So the cold air escapes instead.

That happened relatively infrequently in the 1990s, but since 2000 it has happened nearly every year, according to a study published Tuesday in the journal "Nature Communications."

This material is based upon work supported by the National Science Foundation under Grant No. ANT-0424589. Any opinions, findings, and conclusions or recommendations
expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.